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For the implementation of high-gain dual-band transmit-arrays, adequate unit-cells have to be designed. The potential difficulty is related to the independent 360° phase wrapping needed at each band to compensate arbitrarily large equivalent path length phase compensation. This points to an intractable number of phase combinations at each band, leading to a possibly very large number of different...
A deployable parallel-plate slot array antenna is being developed for the Synthetic Aperture Radar (SAR) sensor onboard small satellite. This parallel-plate slot array antenna is designed to operate in X-band frequency with vertically polarized radiation. The antenna is designed entirely by using HFSS simulator. From the results of simulation, it is shown that at the center frequency (9.65 GHz), one...
Near Vertical Incidence Skywave communication solutions are known to be reliable and quickly deployable, but modeling a suitable radio link requires a good prediction of the ionosphere behavior and insights regarding ionospheric propagation. Within the framework of the national PN-II SIRIUS project, the Technical University of Cluj-Napoca has acquired, installed, and employed the NovAtel GPStation-6...
A new design concept of a compact satellite antenna module for automotive application is presented, enabling mobile reception of all common navigation systems, e.g. GPS in L1&L2 bands, Galileo, GLONASS, BeiDou, as well as reception of satellite digital audio radio service (SDARS). A new design concept allows easy fabrication in combination with high reception properties. The performance of the...
The paper considers a backhaul network for Ka-band. In this band, antenna arrays must employ large number of elements with appropriate beamforming techniques to combat the severe path loss. The goal of this paper is to analyze massive antenna arrays under realistic considerations for the use in terrestrial backhaul links. This analysis addresses practical issues from the implementation point of view...
Drop Size Distributions (DSDs) measured with an optical disdrometer in Madrid during 5 years are used to derive the copolar attenuation (CPA) and cross polarization discrimination (XPD) at 19.7 and 39.4 GHz. A full wave Method of Moments (MoM) is utilized to calculate specific attenuation and phase rotation through a realistic scattering raindrop model for large raindrops. The best-fit parameters...
Universidad Politécnica de Madrid (UPM) is participating in the Alphasat propagation experiment by measuring the copolar level of the Q-Band beacon at 39.4 GHz since April 2014. In this paper the results of the first two complete years of measurements (until March 2016) are presented with regards to excess and total attenuation. The reference level is calculated on an event-by-event basis in the first...
The paper gives a description of the satellite propagation measurement site established in Ljubljana. It consists of two beacon receivers, measuring the Alphasat and Astra 3B beacons at Ka-band and at Q-band, and of a co-located rain gauge. Statistical analysis of collected measurements is performed to create complementary cumulative distribution functions of excess attenuation and rain rate. First...
For the last decades satellite communication systems have been moving towards higher and higher frequencies; rain attenuation along the Earth-satellite path can be an important limiting factor for the system availability, especially in tropical regions where rain events can be particularly intense. One of the possible countermeasures is site diversity. In this paper we evaluate the performance of...
EUTELSAT's first HTS system, KA-SAT, is still the largest in Europe and a benchmark. Since then EUTELSAT has launched EUTELSAT 36C to deliver services over Russia and EUTELSAT 65 West A over LATAM. The Broadband for Africa HTS satellite is currently in production to provide services over Africa. The requirements for HTS systems evolve and are mainly driven by economics trying to drive the cost of...
The paper provides an overview of the most significant space antenna products and technologies for Observation, Exploration and Navigation (OEN) developed by ThalesAleniaSpace-Italia (TAS-I) over more than 30 years. These antennas provided a determinant contribution to the scientific community in understanding earth environment and solar planets. An outline of today key developments is also presented.
In this paper, a data classification method for analyzing the aspects of Signal-to-Noise Ratio (SNR) for Global Navigation Satellite System (GNSS) in real conditions is introduced. Different parts of measured environments and the orbital information of satellites are used as criteria for data classification. It consists of: 1) taking fish eye images of measured routes; 2) dividing measured environments...
Reliable estimates of satellite channel characteristics are of great importance for satellite communications, especially with use of even higher frequencies as Ka-band and in near future Q- and V-band. At a given rain rate the shape of rain drop size distributions (DSDs) considerably influences the corresponding specific attenuation. In previous work it was shown, that annual DSD statistics give evidence...
The attenuation due to rain is one of the main impairments in satellite communications. It is well known that rain attenuation is dependent on the elevation angle of the link, being more severe at low elevation angles; this has a definite impact on the design of TLC and data download systems based on low earth orbit (LEO) satellites. As measurements at various elevation angles are seldom available,...
The employment of optical frequencies in satellite communication systems has been proposed in order to cover the huge needs for capacity in the next decade. The reliable design and the prediction of the performance of optical satellite links need accurate channel modeling in the form of time series generators. Considering cloud free line-of-sight (CFLOS) satellite links, turbulence effects on the...
This paper presents an overview of the activities performed by the Agency in the framework of the Alphasat Aldo Paraboni scientific experiment at Ka and Q band. In particular it addresses the technological developments for the equipment of the propagation campaign, the execution of mission related activities, the execution of propagation campaigns, the international cooperation with the group of propagation...
The Alphasat telecommunication satellite was launched in July, 2013 and beside of the main payload it carries four scientific experiments. One of them is the Aldo Paraboni Scientific Experiment, a propagation experiment in the Ka and Q radio bands. The experiment is coordinated by the European Space Agency under the framework of ARTES 8 Telecom program. Hungary, similarly to other European experimenters...
To illuminate a certain footprint on Earth, a corresponding aperture distribution of the antenna in space needs to be generated. There are various possibilities to generate this distribution. A general classification is for example the distinction between direct radiation and radiation via reflecting apertures. The way in which the illumination is realised is directly linked to the complexity of the...
This paper presents a compact X-band antenna with an isoflux radiation pattern and circular polarization. It consists of a miniaturized helix antenna connected to a stripline circuit that provides a sequential rotation feeding. The antenna is arranged over a vertically corrugated ground plane and it has been optimized for a CubeSat 3U nano-satellite platform. Its design, manufacture and results are...
This paper proposes a new approach to reduce weight and complexity of VHF/UHF cubesat antennas by utilizing a dual band antenna, rather than standard two-antenna system routinely implemented in cubesats. Three systems are compared: A standard system with separate transmit/receive dipoles, a dual-band dipole for both transmit and receive and a dual-band monopole, which uses the body of 1U cubesat (10...
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